From f9807401933263de4d8b9c8ea11683a3e1b04568 Mon Sep 17 00:00:00 2001
From: David Stansby <dstansby@gmail.com>
Date: Fri, 16 Jul 2021 19:21:55 +0100
Subject: [PATCH] Fix .date for EUI maps

---
 changelog/5462.bugfix.rst                  | 5 +++++
 sunpy/map/sources/solo.py                  | 7 +++++++
 sunpy/map/sources/tests/test_eui_source.py | 4 +++-
 3 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 changelog/5462.bugfix.rst

diff --git a/changelog/5462.bugfix.rst b/changelog/5462.bugfix.rst
new file mode 100644
index 00000000000..f3b5c585967
--- /dev/null
+++ b/changelog/5462.bugfix.rst
@@ -0,0 +1,5 @@
+The date returned by `~sunpy.map.GenericMap.date` for Solar Orbiter/EUI maps
+has been adjusted to be taken from the DATE-AVG keyword
+(the middle of the image acquisition period), instead of the DATE-OBS
+keyword (the beginning of the image acquisition period). This means the observer
+coordinate now has the correct date.
diff --git a/sunpy/map/sources/solo.py b/sunpy/map/sources/solo.py
index f022f63b8a5..021ea0f8a05 100644
--- a/sunpy/map/sources/solo.py
+++ b/sunpy/map/sources/solo.py
@@ -8,6 +8,7 @@
 from sunpy.coordinates import HeliocentricInertial
 from sunpy.map import GenericMap
 from sunpy.map.sources.source_type import source_stretch
+from sunpy.time import parse_time
 
 __all__ = ['EUIMap']
 
@@ -47,6 +48,12 @@ def processing_level(self):
     def exposure_time(self):
         return self.meta.get('xposure', 0.0) * self.timeunit
 
+    @property
+    def date(self):
+        t = self.meta.get('date-avg')
+        timesys = self.meta.get('timesys')
+        return parse_time(t, scale=timesys.lower())
+
     @property
     def _supported_observer_coordinates(self):
         return [(('hcix_obs', 'hciy_obs', 'hciz_obs'),
diff --git a/sunpy/map/sources/tests/test_eui_source.py b/sunpy/map/sources/tests/test_eui_source.py
index c106b07dc73..2f4bc4c5594 100644
--- a/sunpy/map/sources/tests/test_eui_source.py
+++ b/sunpy/map/sources/tests/test_eui_source.py
@@ -242,7 +242,9 @@ def test_is_datasource_for(eui_fsi_map):
 
 
 def test_observer_coordinate(eui_fsi_map):
-    assert isinstance(eui_fsi_map.observer_coordinate, SkyCoord)
+    obs_coord = eui_fsi_map.observer_coordinate
+    assert isinstance(obs_coord, SkyCoord)
+    assert obs_coord.obstime.isot == eui_fsi_map.meta['date-avg']
 
 
 def test_observatory(eui_fsi_map):